some people say that when a nation starts to spend more in the debt interest than their defense budget this is also a signal that they'll fall soon and this is happening to the us as well
so, nobody can know for sure but it definitely is a possibility
And again when the current president of US, Mr. Trump had embraced Bitcoin and announced it as a strategic reserve, countries that patronize the dollar might not see any need for using dollar anymore. At least we already know that the China and Russia agreement was not in dollar. So as the users (Countries) of dollars begin to think deeper regards making bitcoin a strategic reserve, they might give an interpretation that might not make them keep dollar as their reserve because many countries reserve there money in dollar, also cost and value it in dollar. Therefore making agreement to use bitcoin for bilateral transactions and dollar would begin to lose value.
Think on the brighter side of things. If you look well the dollars wont lose value if people dont reserve it anymore because they will surely reserve it. Trump policies will make the dollar gain value when they reserve bitcoin, but there will be regulations on the dollar directly as the price of bitcoin keeps fluctuating. At the time the US will sell their reserved bitcoins dollar will skyrocket too so for those who hold their dollar before then will be on major profit.